Customer relationship management (CRM) is the integrated management of an organization’s interactions with customers, “customers” being broadly defined.
At its most basic, CRM provides a turbocharged contact manager, helping the user segment and track “customers” (contacts, leads, users, suppliers, constituents, etc.). This is the extent of my own needs, so this roundup of offerings is slanted toward simple contact management solutions that can be locally installed. Having acknowledged that, CRM properly understood is far more and for that reason many solutions are quite complex.
Some CRMs are available only as software as a service (SaaS), meaning you subscribe to an online service accessed via a web browser. There’s nothing to install, and conversely you cannot audit or customize the code. Other CRM providers are more flexible and make their code available for installation either onsite or online.
CiviCRM: LAMP application. Open source available for download at no cost or as paid SaaS from third parties. Oriented towards nonprofits, and as far as I know is peerless in this niche. Large ecosystem of third-party consultants and hosts. Not stand-alone; it runs as an extension to the popular web content management systems Drupal, Joomla, and WordPress. Complex; expect to invest heavily in setup, configuration, and end-user training. I know of no simpler solution that is appropriate for nonprofits.
Dolibarr: LAMP application. Open source available for download at no cost. Oriented toward small businesses. Popular. Reputed to be the easiest to use CRM. Tops my list of CRMs to try.
SugarCRM: LAMP application. Open source available for download at no cost; paid proprietary versions add features. Popular and well-regarded; the standard by which others are judged. Large ecosystem of third-party consultants and hosts. Easy to install.
Vtiger: LAMP application. Open source available for download at no cost or as paid SaaS operated by the developers. Fork of the popular SugarCRM and popular in its own right. Suffers persistent security issues, bugs, and slow developer response to issues. For example, as of 2013 the latest stable version used functions that were removed from PHP in 2009 (!), and there is still no official acknowledgement of the issue.
Zoho CRM: SaaS. No cost for limited functionality version; paid versions add features. Attractive; easy to set up and use. Popular and well-regarded. No cost version is quite limited and should be considered merely a free trial.